Red phosphorescent composition and organic electroluminescent device using the same

ABSTRACT

A red phosphorescent compound, includes a host material being capable of transporting an electron or a hole; and a dopant material represented by the following formula 1: 
                         
wherein each of R1 to R4 is selected from the group consisting of hydrogen atom (H), C1 to C6 alkyl and C1 to C6 alkoxy, and at least one of R1 to R4 is C1 to C6 alkyl, and wherein each of R5 to R7 is selected from the group consisting of hydrogen, C1 to C6 alkyl and pyrrole, and at least one of R5 to R7 is pyrrole, and wherein each of X and Y is selected from the group consisting of H, non-substituted C1 to C6 alkyl and C1 to C6 alkyl substituted by fluorine.

The present application claims the benefit of Korean Patent ApplicationNo. 10-2008-0106547 filed in Korea on Oct. 29, 2008, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a red phosphorescent compound and anorganic electroluminescent device (OELD) and more particularly to a redphosphorescent compound having high color purity, high luminescentefficiency and improved lifetime and an OELD using the redphosphorescent compound.

2. Discussion of the Related Art

Recently, a requirement for a flat panel display device having arelatively large display area and a relatively small occupancy has beenincreased. Among the flat panel display devices, an OELD has variousadvantages as compared to an inorganic electroluminescent device, aliquid crystal display device, a plasma display panel, and so on. TheOELD device has excellent characteristics of viewing angle, contrastratio, and so on. Also, since the OELD device does not require abacklight assembly, the OELD device has low weight and low powerconsumption. Moreover, the OELD device has advantages of high responserate, low production, cost and so on.

In general, the OELD emits light by injecting electrons from a cathodeand holes from an anode into an emission compound layer, combining theelectrons with the holes, generating an exciton, and transforming theexciton from an excited state to a ground state. A flexible substrate,for example, a plastic substrate, can be used as a base substrate whereelements are formed. The OELD has excellent characteristics of viewingangle, contrast ratio, and so on. Also, since the OELD does not requirea backlight assembly, the OELD has low weight and low power consumption.Moreover, the OELD has advantages of a high response rate, lowproduction cost, high color purity, and so on. The OELD can be operatedat a voltage (e.g., 10V or below) lower than a voltage required tooperate other display devices. In addition, the OELD is adequate toproduce full-color images.

A general method for fabricating OELDs will be briefly explained below.First, an anode is formed on a substrate by depositing a transparentconductive compound, for example, indium-tin-oxide (ITO). Next, a holeinjection layer (HIL) is formed on the anode. For example, the HIL maybe formed of copper phthalocyanine (CuPC) and have a thickness of about10 nm to about 30 nm. Next, a hole transporting layer (HTL) is formed onthe HIL. For example, the HTL may be formed of4,4′-bis[N-(1-naphthyl)-N-phenylamino]-biphenyl (NPB) and have athickness of about 30 nm to about 60 nm. Next, an emitting compoundlayer (EML) is formed on the HTL. A dopant may be doped onto the EML. Ina phosphorescent type, the EML may be formed of4,4′-N,N′-dicarbazole-biphenyl (CBP) and have a thickness of about 30 nmto about 60 nm, and the dopant may includes one of iridium complexrepresented by following Formulas 1-1 to 1-3.

Next, an electron transporting layer (ETL) and an electron injectionlayer (EIL) are stacked on the EML. For example, the ETL may be formedof tris(8-hydroxy-quinolate)aluminum (Alq3). A cathode is formed on theEIL, and a passivation layer is formed on the cathode.

In the above structure, the EML produces red, green and blue colors suchthat the OELD can display full-color images. In an emitting compound, anexciton is generated by combining the electrons from a cathode and holesfrom an anode. The exciton includes a singlet exciton and a tripletexciton. The singlet exciton participates in a fluorescent typeemission, while the triplet exciton participates in a phosphorescenttype emission. The singlet exciton has a formation probability of about25%, while the triplet exciton has a formation probability of about 75%.Accordingly, the phosphorescent type emission has luminescenceefficiency greater than the fluorescent type emission.

In the phosphorescent compound, since a red phosphorescent compound hasexcellent luminescence efficiency as compared to a red fluorescentcompound, the red phosphorescent compound has been widely developed andresearched to improve an emission efficiency of the OELD. Thephosphorescent compound is required to have high luminescenceefficiency, high color purity, long life span, and so on. Particularly,as shown in FIG. 1, as the color purity of an OELD using a redphosphorescent material becomes higher (i.e. as the X index on CIEchromaticity coordinates increase), the relative spectral sensitivity ofimages from the OELD decreases. Accordingly, it is difficult to achievehigh luminance efficiency of the OELD.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a red phosphorescentcompound and an organic electroluminescent device (OELD) using the samethat substantially obviates one or more of the problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a red phosphorescentcompound having high color purity (e.g., X index of CIE chromaticitycoordinates being greater than 0.65), high luminescence efficiency, andlong lifetime.

Another object of the present invention is to provide an OELD deviceusing the red phosphorescent compound.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, ared phosphorescent composition, includes a host material being capableof transporting an electron or a hole; and a dopant material representedby following Formula 1:

wherein each of R1 to R4 is selected from the group consisting ofhydrogen atom (H), C1 to C6 alkyl and C1 to C6 alkoxy, and at least oneof R1 to R4 is C1 to C6 alkyl, and wherein each of R5 to R7 is selectedfrom the group consisting of hydrogen, C1 to C6 alkyl and pyrrole, andat least one of R5 to R7 is pyrrole, and wherein each of X and Y isselected from the group consisting of H, non-substituted C1 to C6 alkyland C1 to C6 alkyl substituted by fluorine, wherein nitrogen of pyrrolein at least one of R5 to R7 is combined with quinoline in the Formula 1.

In another aspect of the present invention, an organicelectroluminescent device includes a first substrate; a thin filmtransistor on the first substrate; a second substrate facing the firstsubstrate; and an organic luminescent diode electrically connected tothe thin film transistor and including a first electrode, a secondelectrode facing the first electrode and an organic emission layerdisposed between the first and second electrodes, a red phosphorescentcomposition of the organic emission layer including a host materialbeing capable of transporting an electron or a hole; and a dopantmaterial represented by following Formula 1:

wherein each of R1 to R4 is selected from the group consisting ofhydrogen atom (H), C1 to C6 alkyl and C1 to C6 alkoxy, and at least oneof R1 to R4 is C1 to C6 alkyl, and wherein each of R5 to R7 is selectedfrom the group consisting of hydrogen, C1 to C6 alkyl and pyrrole, andat least one of R5 to R7 is pyrrole, and wherein each of X and Y isselected from the group consisting of H, non-substituted C1 to C6 alkyland C1 to C6 alkyl substituted by fluorine, wherein nitrogen of pyrrolein at least one of R5 to R7 is combined with quinoline in the Formula 1.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a graph showing a relation of a color purity and a visibledegree; and

FIG. 2 is a schematic cross-sectional view of an OELD according to thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments,examples of which are illustrated in the accompanying drawings.

A red phosphorescent compound includes at least one alkyl, which issubstituted in a phenyl part, and at least one pyrrole, which issubstituted in a quinoline part, such that the red phosphorescentcompound has improved color purity, luminescence efficiency and lifetime. The red phosphorescent compound is represented by the followingFormula 2.

In the above Formula 2, each of R1 to R4 is selected from the groupconsisting of hydrogen atom (H), C1 to C6 alkyl and C1 to C6 alkoxy. Inaddition, at least one of R1 to R4 is C1 to C6 alkyl. Each of R5 to R7is selected from the group consisting of H, C1 to C6 alkyl and pyrrole.In addition, at least one of R5 to R7 is pyrrole.

As mentioned above, at least one alkyl is substituted in a first phenylpart “A” such that the red phosphorescent compound has improved colorpurity and luminescence efficiency. In addition, at least one pyrrole issubstituted in a second phenyl part “B”, which is not substituted bynitrogen, in a quinoline part such that the red phosphorescent compoundhas further improved color purity and luminescence efficiency andelongated lifetime.

In Formula 2, each of X and Y is selected from the group consisting ofH, non-substituted C1 to C6 alkyl and C1 to C6 alkyl substituted byfluorine.

For example, the C1 to C6 alkyl may be selected from the groupconsisting of methyl, ethyl, n propyl, i-propyl, n-butyl, i-butyl andt-butyl, and the C1 to C6 alkoxy may be selected from the groupconsisting of methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxyand t-butoxy.

As a result, in the above Formula 2, a left side structure of centraliridium (Ir) is selected from the following Formula 3.

In addition, in the above Formula 2, a right side structure of centraliridium (Ir) is selected from the following Formulas 4-1 to 4-8. Thestructures of the Formulas 4-1 to 4-8 are 2,4-pentanedione,2,2,6,6-tetramethylheptane-3,5-dione, 1,3-propanedione, 1,3-butanedione,3,5-heptanedione, 1,1,1-trifluoro-2,4-pentanedione,1,1,1,5,5,5-hexafluoro-2,4-pentanedione and2,2-dimethyl-3,5-hexanedione, respectively.

As a result, the red phosphorescent compound represented by Formula 2 isselected from the following Formula 5. For convenience of explanation,the references of A1 to A60 are marked on each compound.

SYNTHESIS EXAMPLE

A synthesis example of the red phosphorescent compound represented byA-1 in the Formula 5 is explained. The red phosphorescent compound ofA-1 is iridium(III){2-(3-methylphenyl)-6-(1H-pyrrole-1-yl)quinoline-N,C^(2′)}(2,4-pentanedionate)-0,0).

1. Synthesis of 2-(3-methylphenyl)-6-(1H-pyrrole-1-yl)quinoline

2-(3-methylphenyl)-6-(1H-pyrrole-1-yl)quinoline is synthesized byfollowing Reaction Formula 1.

3-methylphenyl boronic acid (13 mmol), 2-chloro-6-fluoroquinoline (10mmol), tetrakis(triphenylphosphine)palladium(0) (0.5 mmol) and potassiumcarbonate (15 g) are put in a two-neck round-bottom flask and dissolvedin tetrahydrofuran (THF) (30 mL) and H₂O (10 mL). Subsequently, theresulting solution is stirred in a bath under a temperature of about100° C. for 24 hours. After completion of the reaction, THF and tolueneare removed. The reaction mixture is extracted with dichloromethane andwater, and then being distilled under reduced pressure. The resultingresidence is filtered by silica gel column and distilled under reducedpressure again. Next, by re-crystallizing and filtering,2-(3-methylphenyl)-6-(1H-pyrrole-1yl)quinoline (1.4 g) is yielded.

2. Synthesis of Chloro-Bridged Dimmer Complex

Chloro-bridged dimmer complex is synthesized by following ReactionFormula 2.

Iridium chloride (5 mmol) and2-(3-methylphenyl)-6-(1H-pyrrole-1-yl)quinoline (10 mmol) is put in amixed solvent (30 mL), where a ratio of 2-ethoxyethanol to distilledwater is 3:1. The mixture is refluxed for 24 hours, and water is addedthereto. The resulting solid is filtered and washed by distilled waterto yield chloro-bridged dimmer complex.

3. Synthesis of iridium(III){2-(3-methylphenyl)-6-(1H-pyrrole-1-yl)quinoline-N,C^(2′)}(2,4-pentanedionate-0,0)

Iridium(III){2-(3-methylphenyl)-6-(1H-pyrrole-1-yl)quinoline-N,C^(2′)}(2,4-pentanedionate-0,0) is synthesized by following Reaction Formula 3.

Chloro-bridged dimmer complex (1 mmol), 2,4-pentanedione (3 mmol) andsodium carbonate (Na₂CO₃) (6 mmol) is put in 2-ethoxyethanol (30 mL),and is refluxed. The resulted mixture is cooled to a room temperature,and then distilled water is added thereto. The mixture is filtered. Theresulted solid is dissolved in dichloromethane, and then is filtered bysilica gel column. By re-crystallizing the resulted solution usingdichloromethane and methanol to yield the red phosphorescent compound ofA-1 in Formula 5.

Hereinafter, a detailed description will be made of preferred examplesassociated with the OELD according to the present invention. Morespecifically, the examples relate to an OELD including an emissionmaterial layer which uses the red phosphorescent compound of Formula 2as a dopant.

EXAMPLES Example 1

An indium-tin-oxide (ITO) layer is pattered on a substrate and washedsuch that an emission area of the ITO layer is 3 mm*3 mm. The substrateis loaded in a vacuum chamber, and the process pressure is adjusted to1*10⁻⁶ torr. CuPC (about 200 angstroms),4,4′-bis[N-(1-naphthyl)-N-phenylamino]-biphenyl (NPD) (about 400angstroms), aluminum(III)bis(2-methyl-8-quinolinato)-4-phenylphenolate(BAlq)+A-1 compound (about 5 weight %) (about 200 angstroms), Alq3(about 300 angstroms), fluorolithium (LiF) (about 5 angstroms) andaluminum (Al) (about 1000 angstroms) are sequentially formed on the ITOlayer such that an OELD is fabricated.

When the A-1 red phosphorescent compound is used as a dopant for anemission layer, the OELD produce a brightness of 1513 cd/m² at anelectric current of 0.9 mA and a voltage of 5.7 V. At this time, the Xindex and Y index of CIE color coordinates are 0.667 and 0.331,respectively. In addition, the OELD has a lifetime of 5700 hours at 2000cd/m². The lifetime is defined as the time taken before the luminance ofthe OELD decreases to half its initial value.

Example 2

An ITO layer is pattered on a substrate and washed such that an emissionarea of the ITO layer is 3 mm*3 mm. The substrate is loaded in a vacuumchamber, and the process pressure is adjusted to 1*10⁻⁶ torr CuPC (about200 angstroms), NPD (about 400 angstroms), BAlq+A-13 compound (about 5weight %) (about 200 angstroms), A1q3 (about 300 angstroms), LiF (about5 angstroms) and A1 (about 1000 angstroms) are sequentially formed onthe ITO layer such that an OELD is fabricated.

When the A-13 red phosphorescent compound is used as a dopant for anemission layer, the OELD produce a brightness of 1595 cd/m² at anelectric current of 0.9 mA and a voltage of 5.6 V. At this time, the Xindex and Y index of CIE color coordinates are 0.672 and 0.325,respectively. In addition, the OELD has a lifetime of 6800 hours at 2000cd/m².

Example 3

An ITO layer is pattered on a substrate and washed such that an emissionarea of the ITO layer is 3 mm*3 mm. The substrate is loaded in a vacuumchamber, and the process pressure is adjusted to 1*10⁻⁶ torr. CuPC(about 200 angstroms), NPD (about 400 angstroms), BAlq+A-5 compound(about 5 weight %) (about 200 angstroms), A1q3 (about 300 angstroms),LiF (about 5 angstroms) and A1 (about 1000 angstroms) are sequentiallyformed on the ITO layer such that an OELD is fabricated.

When the A-5 red phosphorescent compound is used as a dopant for anemission layer, the OELD produce a brightness of 1012 cd/m² at anelectric current of 0.9 mA and a voltage of 5.4 V. At this time, the Xindex and Y index of CIE color coordinates are 0.682 and 0.310,respectively. In addition, the OELD has a lifetime of 4500 hours at 2000cd/m².

Comparative Example 1

An ITO layer is pattered on a substrate and washed such that an emissionarea of the ITO layer is 3 mm*3 mm. The substrate is loaded in a vacuumchamber, and the process pressure is adjusted to 1*10⁻⁶ torr. CuPC(about 200 angstroms), NPD (about 400 angstroms), BAlq+[Formula 1-1]compound (about 7 weight %) (about 200 angstroms), Alq3 (about 300angstroms), LiF (about 5 angstroms) and A1 (about 1000 angstroms) aresequentially formed on the ITO layer such that an OELD is fabricated.

When the [Formula 1-1] red phosphorescent compound is used as a dopantfor an emission layer, the OELD produce a brightness of 1173 cd/m² at anelectric current of 0.9 mA and a voltage of 6.0 V. At this time, the Xindex and Y index of CIE color coordinates are 0.606 and 0.375,respectively. In addition, the OELD has a lifetime of 4000 hours at 2000cd/m².

Comparative Example 2

An ITO layer is pattered on a substrate and washed such that an emissionarea of the ITO layer is 3 mm*3 mm. The substrate is loaded in a vacuumchamber, and the process pressure is adjusted to 1*10⁻⁶ torr. CuPC(about 200 angstroms), NPD (about 400 angstroms), BAlq+[Formula 1-2]compound (about 7 weight %) (about 200 angstroms), Alq3 (about 300angstroms), LiF (about 5 angstroms) and A1 (about 1000 angstroms) aresequentially formed on the ITO layer such that an OELD is fabricated.

When the [Formula 1-2] red phosphorescent compound is used as a dopantfor an emission layer, the OELD produce a brightness of 780 cd/m² at anelectric current of 0.9 mA and a voltage of 7.5 V. At this time, the Xindex and Y index of CIE color coordinates are 0.659 and 0.329,respectively. In addition, the OELD has a lifetime of 2500 hours at 2000cd/m².

Herein, CuPC, BAlq, Alq3 are represented by following Formulas 6 to 8,respectively. BAlq is used for an emission material layer. However, theemission material layer may be formed of other materials. For example,A1 metallic complex, zinc (Zn) metallic complex or CBP may be used forthe emission material layer. CBP is a carbazole derivatives andrepresented by following Formula 9.

The OELD fabricated in Examples 1 to 3 and Comparative Examples 1 and 2are evaluated for efficiency, brightness, lifetime, and so on. A voltagehas a dimension of [V], an electric current has a dimension of [mA], abrightness has a dimension of [cd/m2], a current efficiency has adimension of [cd/A], a power efficiency has a dimension of [1 m/W], aninternal quantum efficiency has a dimension of [%], and a lifetime has adimension of [hour]. The evaluated results are shown in Table 1.

TABLE 1 Internal Electric Current Power quantum voltage currentBrightness efficiency efficiency efficiency CIE(X) CIE(Y) lifetime Ex. 15.7 0.9 1513 15.1 7.5 18.4 0.667 0.331 5700 Ex. 2 5.6 0.9 1595 15.9 7.219.5 0.672 0.325 6800 Ex. 3 5.4 0.9 1012 10.1 8.3 18.1 0.682 0.310 4500Com. 6.0 0.9 1173 11.73 6.2 12.0 0.606 0.375 4000 Ex. 1 Com. 7.5 0.9 7807.8 3.3 10.4 0.659 0.329 2500 Ex. 2

As shown in TABLE 1, the OELD in Examples 1 to 3 has high color purity(e.g., CIE(X)>0.65) and high internal quantum efficiency. Accordingly,the OELD according to the present invention has improved luminescenceefficiency. As a result, when the red phosphorescent compound of thepresent invention as a dopant for an emission material layer of an OELD,the OELD has high color purity, high brightness and high luminescenceefficiency. In addition, the OELD has elongated lifetime.

FIG. 2 is a schematic cross-sectional view of an OELD according to thepresent invention. In FIG. 2, an OELD 100 includes a first substrate101, where a switching element (not shown) and a driving element DTr areformed, and a second substrate 150 where an organic light emitting diodeE is formed. Each of the switching element and the driving element DTrmay be a thin film transistor.

Although not shown, the first and second substrates 101 and 151 areattached by a seal pattern formed in their boundary. An absorbent isformed inner side of the seal pattern. A gate line and a data line crosseach other to define a pixel region P on the first substrate 101. Theswitching element is formed at a crossing portion of the gate and datalines, and the driving element DTr is connected to the switchingelement. The driving element DTr includes a gate electrode 103, a gateinsulating layer 106, a semiconductor layer 110, a source electrode 117and a drain electrode 119. For example, the semiconductor layer 110includes an active layer 110 a of intrinsic amorphous silicon and anohmic contact layer 110 b of impurity-doped amorphous silicon. Thedriving element DTr having a bottom gate type shown in FIG. 2. However,the driving element has a top gate type wherein polycrystalline siliconmay be used for the semiconductor layer.

A passivation layer 122 having a drain contact hole 125, which exposes aportion of the drain electrode 119 of the driving element DTr, is formedover the switching element and the driving element DTr. A connectionelectrode 130 is formed on the passivation layer and contacts the drainelectrode 119 of the driving element DTr through the drain contact hole125.

A first electrode 155 is formed on an entire surface of the secondsubstrate 151. The first electrode 155 is formed of a material having alarge work function and serves as an anode. For example, the firstelectrode 155 may be formed of ITO. A column spacer 158 corresponding tothe connection electrode 158 on the first substrate 151 is formed.

An organic emission layer 176 including red, green and blue emissionpatterns is formed on the first electrode 155. The red, green and blueemission patterns correspond to the pixel region P. A second electrode180 is formed on the organic emission layer 176 in each pixel region P.The second electrode 180 is formed of a material having a small workfunction and serves as a cathode. For example, the second electrode 180may be formed of one of Al and Al alloy (AlNd). The second electrode 180on the column spacer 158 contacts the connection pattern 130 on thefirst substrate 101.

In addition, a wall 173 is formed on the first electrode 155. The wall173 corresponds to boundaries of the pixel region P. Namely, the wall173 corresponds to the gate and data lines on the first substrate 101.The wall 173 has a reverse taper shape. In more detail, across-sectional view of the wall 173 taken along a vertical line to thesecond substrate 151 has a wide side adjacent to the second substrate151 and a wide side far to the second substrate 151. Due to the wall173, the organic emission layer 176 and the second electrode 180 areseparated in each pixel region P. A buffer layer 168 may be furtherformed between the wall 173 and the first electrode 155, and anauxiliary electrode 165 may be further formed between the buffer layer168 and the first electrode 155. The auxiliary electrode 165 is formedof a low resistance metallic material such that a voltage can beefficiently applied to the first electrode 165. The buffer layer 168 andthe auxiliary electrode 165 may be omitted.

Although not shown, to maximize luminescence efficiency, the organicemission layer 176 has a multiple-layered structure. For example, a holeinjection layer (HIL), a hole transporting layer (HTL), an emittingmaterial layer (EML), an electron transporting layer (ETL) and anelectron injection layer (EIL) are stacked on the first electrode 155.In this case, the red emission pattern of the EML includes a hostmaterial, which is capable of transporting an electron and a hole, andthe red phosphorescent compound as a dopant. The red phosphorescentcompound according to the present invention is represented by the above[Formula 2]. The red phosphorescent compound as a dopant is added with arange of about 0.1 weight % to about 50 weight % with respect to a totalweight of a material in the red emission pattern. The host material maybe formed of one of BAlq, Al metal complex, Zn metal complex andcarbazole derivatives, for example, CBP. A ligand of Al metal complexand Zn metal complex may be one of quinolnyl, biphenylyl, isoquinolnyl,phenylyl, methylquinolnyl, dimethylquinolnyl and dimethyl-iso-quinolnyl.Each of the green and blue emission patterns also includes aphosphorescent compound.

On the other hand, in FIG. 2, the driving element DTr is disposed on thefirst substrate 101, while the organic luminescent diode E is disposedon the second substrate 151. In addition, since the first electrode 155is formed of transparent ITO, light from the organic luminescent diode Epasses through the second substrate 151. It is called as a top emissiontype. However, both the driving element DTr and the organic luminescentdiode E may be disposed on the same substrate. The second electrode maybe formed of a transparent material, while the first electrode may beformed of an opaque material. In this case, light from the organicluminescent diode passes through the first substrate. It is called as abottom emission type. The OELD of the present invention can be appliedto any of the top and bottom emission types.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A red phosphorescent composition, comprising: a host material beingcapable of transporting an electron or a hole; and a dopant materialrepresented by following Formula 1:

wherein each of R1 to R4 is selected from the group consisting ofhydrogen atom (H), C1 to C6 alkyl and C1 to C6 alkoxy, and at least oneof R1 to R4 is C1 to C6 alkyl, and wherein each of R5 to R7 is selectedfrom the group consisting of hydrogen, C1 to C6 alkyl and pyrrole, andat least one of R5 to R7 is pyrrole, and wherein each of X and Y isselected from the group consisting of H, non-substituted C1 to C6 alkyland C1 to C6 alkyl substituted by fluorine, wherein nitrogen of pyrrolein at least one of R5 to R7 is combined with quinoline in the Formula 1.2. The composition according to claim 1, wherein the C1 to C6 alkyl isselected from the group consisting of methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl and t-butyl.
 3. The composition according to claim 1,wherein the C1 to C6 alkoxy is selected from the group consisting ofmethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy and t-butoxy.4. The composition according to claim 1, wherein the dopant material hasa weight % of about 0.1 to about 50 with respect to a total weight ofthe composition.
 5. The composition according to claim 1, wherein thehost material is selected from the group consisting ofaluminum(III)bis(2-methyl-8-quinolinato)-4-phenylphenolate (BAlq), Almetal complex, Zn metal complex and carbazole derivative.
 6. Thecomposition according to claim 5, wherein the carbazole derivative is4,4′-N,N′-dicarbazole-biphenyl (CBP).
 7. An organic electroluminescentdevice, comprising: a first substrate; a thin film transistor on thefirst substrate; a second substrate facing the first substrate; and anorganic luminescent diode electrically connected to the thin filmtransistor and including a first electrode, a second electrode facingthe first electrode and an organic emission layer disposed between thefirst and second electrodes, a red phosphorescent composition of theorganic emission layer including: a host material being capable oftransporting an electron or a hole; and a dopant material represented byfollowing Formula 1:

wherein each of R1 to R4 is selected from the group consisting ofhydrogen atom (H), C1 to C6 alkyl and C1 to C6 alkoxy, and at least oneof R1 to R4 is C1 to C6 alkyl, and wherein each of R5 to R7 is selectedfrom the group consisting of hydrogen, C1 to C6 alkyl and pyrrole, andat least one of R5 to R7 is pyrrole, and wherein each of X and Y isselected from the group consisting of H, non-substituted C1 to C6 alkyland C1 to C6 alkyl substituted by fluorine, wherein nitrogen of pyrrolein at least one of R5 to R7 is combined with quinoline in the Formula 1.8. The device according to claim 7, wherein the C1 to C6 alkyl isselected from the group consisting of methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl and t-butyl.
 9. The device according to claim 7,wherein the C1 to C6 alkoxy is selected from the group consisting ofmethoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy and t-butoxy.10. The device according to claim 7, wherein the dopant material has aweight % of about 0.1 to about 50 with respect to a total weight of thecomposition.
 11. The device according to claim 7, wherein the hostmaterial is selected from the group consisting ofaluminum(III)bis(2-methyl-8-quinolinato)-4-phenylphenolate (BAlq), Almetal complex, Zn metal complex and carbazole derivative.
 12. The deviceaccording to claim 11, wherein the carbazole derivative is4,4′-N,N′-dicarbazole-biphenyl (CBP).
 13. The device according to claim7, wherein the organic emission layer has a stacked structure of a holeinjection layer, a hole transporting layer, an emission material layer,an electron transporting layer and an electron injection layer.
 14. Thedevice according to claim 7, wherein the organic luminescent diode isformed on the first substrate.
 15. The device according to claim 7,wherein the organic luminescent diode is formed on the second substrate.16. The device according to claim 7, wherein the first electrode isdisposed between the second substrate and the second electrode andformed of a transparent conductive material.
 17. The device according toclaim 7, wherein the second electrode is disposed between the firstsubstrate and the first electrode and formed of a transparent conductivematerial.